Implement MediaSession (metadata) per frame [NOT READY, HAS DEPENDENCY]

third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NavigatorMediaSession_h
+#define NavigatorMediaSession_h
+
+#include "core/frame/DOMWindowProperty.h"
+#include "core/frame/Navigator.h"
+#include "modules/mediasession/MediaSession.h"
+#include "platform/Supplementable.h"
+
+namespace blink {
+
+class Navigator;
+
+class NavigatorMediaSession final : public GarbageCollected<NavigatorMediaSession>, public Supplement<Navigator> {
+    USING_GARBAGE_COLLECTED_MIXIN(NavigatorMediaSession);
+
+public:
+    static NavigatorMediaSession& from(Navigator&);
+    static MediaSession* mediaSession(Navigator&);
+
+    DECLARE_TRACE();
+
+private:
+    NavigatorMediaSession(Navigator&);
+    static const char* supplementName();
+
+    Member<MediaSession> m_session;
+};
+}
+
+#endif // NavigatorMediaSession_h